ORC based micro-cogeneration systems for residential application - A state of the art review and current challenges

This work reviews the use of ORC for micro-CHP applications taking into account the intrinsic requirements of the residential sector. One of those requirements is the ability to face highly variable thermal demand loads for which a short response time is necessary to ensure. The present research analyzes how manufacturers and the researcher centers are dealing with this key requirement. One of the findings of this work is that the referred requirement is essentially dependent on the ORC-evaporator design and how the primary energy reaches the power cycle, while the remaining ORC main components (expander, pump and condenser) play a minor role on that ability. Additionally, this research also offers an analysis of the micro-CHP potential and of the ORC market evolution, presenting a historical perspective of the technology, current main manufacturers, main application areas and a comparison between the use of an organic fluid and water/steam as working fluid for Rankine cycles.